The present disclosure relates to an image forming apparatus having an execution mode where an image forming command is allowed to be received from a user, and a standby mode where the image forming command is not received.
In recent years, in response to the sophistication of image forming apparatuses, known is an image forming apparatus having, as a power switch to be operated by a user, an operational switch for outputting a signal to a control unit of the image forming apparatus when pressed by the user, rather than an open/close switch for directly opening/closing supply of the power-supply voltage. The reasons why supply of a power-supply voltage is not directly opened/closed with a power switch are as follows.
In other words, with a sophisticated image forming apparatus, required is termination processing of shutting down the power after storing the internal state of the apparatus or shutting down the power after completing the currently running process. Thus, in order to maintain the power supply for the control unit to execute the termination processing after the user presses the power switch, the power is not shut down even when the power switch is pressed.
In addition, when the user presses the power switch to turn OFF the power, a signal is sent to the control unit. Subsequently, the control unit switches to a standby state (standby mode) which corresponds to the power OFF state after the termination processing is executed. In other words, in preparation for the case where the user turns ON the power switch for starting the image forming apparatus, the control unit is standing by in a state where a signal from the power switch can be received even in a power OFF state.
In other words, a state where the image forming apparatus is in the standby mode corresponds to a state where the power of the image forming apparatus has been turned OFF when viewed from the user.
When the user turns ON the power switch in the standby state (standby mode), the signal thereof is sent from the power switch to the control unit. Subsequently, the control unit switches to an ON state (execution mode) where image formation can be executed, and executes image formation according to a command from the user.
As described above, in a case where the power OFF state as viewed by the user corresponds to the standby mode and the power ON state as viewed by the user corresponds to the execution mode, when the external power supply to the apparatus is cut off, for example, as a result of the power plug of the image forming apparatus being pulled out of the outlet or due to a power outage, and the power is thereafter restored, it is desirable that the apparatus is started in the mode that was being used before the power shutdown.
Thus, known is an image forming apparatus which detects that the user has turned OFF the power switch, stores the state of the apparatus in a nonvolatile storage medium, and, when the apparatus is restarted, reads the state of the apparatus stored in the nonvolatile storage medium, and performs operations according to the read state.
Meanwhile, a power circuit which generates an operational power-supply voltage for operating the apparatus from a commercial AC power comprises a capacitor for smoothing the power-supply voltage. The capacitor stores a certain degree of power. Thus, even when the external power supply to the image forming apparatus is cut off, supply of the operational power-supply voltage will continue for awhile based on the power stored in the capacitor. The operation of the control unit is consequently continued.
In particular, power consumption in the standby mode is defined, for example, in Lot6 (standby power, OFF mode power consumption reference) of the EuP Directive (Directive on Eco-Design of Energy-using Products). Lot6 prescribes that the power consumption during the standby mode must not exceed 0.5 W. Thus, the power consumption of an image forming apparatus compatible with the EuP Directive is extremely small. Consequently, after the external power supply to the image forming apparatus is cut off, there are cases where the operation of the control unit will continue for several seconds; for instance, for about 6 seconds, based on the power stored in the capacitor.
Consequently, according to the foregoing image forming apparatus, for example, when the external power supply to the apparatus is cut off as a result of the power plug of the image forming apparatus being pulled out of the outlet or due to the occurrence of a power outage, and a signal is thereafter sent from the power switch to the control unit when the user unintentionally touches the power switch, there are cases where the mode that was changed after the power supply shutdown is stored in the nonvolatile storage medium. In the foregoing case, when the power supply is restored and the image forming apparatus is started, the apparatus will be started up based on the mode stored in the nonvolatile storage medium; that is, the mode that was changed after the power supply of the apparatus was shut down.
Nevertheless, since the user will not normally think that the status of the apparatus would change after the power plug is pulled out from the outlet or after the occurrence of a power outage, when the apparatus is started based on the mode that was changed after the previous power shutdown when the power supply is restored, there is a drawback in that the operation of the apparatus becomes unnatural from the user's perspective.
An object of the present disclosure is to provide an image forming apparatus capable of improving the certainty that, when an external power supply is cut off and the supply of power is thereafter resumed, the image forming apparatus will be started in the mode that was being used when the power supply was cut off.